418 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The concentration of the soil solution varied somewhat with the seasons, 

 rainfall, different depths of the soil, and with plant growth. 



It is probable that the variations in the concentration of the soil solution, in 

 some instances at least, have not been sufficiently considered in biological studies 

 where conclusions have been drawn based upon the results obtained from studies 

 of the water extracts of soils. Moreover, it does not seem possible to determine 

 the fertilizer needs of soils by obtaining water extracts and growing plants 

 therein. 



The seasonal variation in the soluble salt content of soils doubtless plays an 

 important r6le in the results obtained from the use of fertilizers. Additional 

 information will be presented later. — F. G. A. 



Soils, Variation in Water Content of. By J. C. Martin and A. W. Christie 

 (Jour. Agr. Res xviii. No. 3, Nov. 1919, pp. 139-144). — The question of the 

 effect "produced on water soluble matters by variations in the moisture content 

 of soils is an important one. It was found that the moisture contents' approaching 

 the air-dry condition show a decided tendency to depress the nitrates and 

 potassium in both soils tested, and the sulphates in silty clay-loam soil. These 

 depressions are reflected in the total dissolved material. The excess water 

 in sandy loam soil causes a disappearance of nitrates, and also depresses the 

 potassium, calcium, and magnesium ; these losses being reflected in the total 

 solids extracted. Considerable variations in moisture contents of soils, provided 

 the saturation point is not reached, do not appreciably modify the results obtained 

 by the water-extraction method. — A. B. 



Sowing various Crops, Factors affecting the Depth of. By F. S. Harris 



and H. J. Maughan (U.S.A. Exp. Stn. Utah, Bull. 164, Sept. 1918, pp. 18; 

 illus., 12 figs.). — A review of other investigators' experiments shows that the 

 largest number of plants and the largest yield were usually obtained from sowing 

 seeds 1 to 2 inches deep. The present experiment was made with Triticum 

 sativum, Avena sativa, Zea Mays, Hordeum vulgar e, Medicago sativa, Pisum 

 arvense, Phaseolus sp., Beta vulgaris, and Sorghum vulgar e. 



Between 1 and 8 inches the depth of sowing seemed to have little effect on 

 the germination of most kinds of seeds, but the highest germination usually 

 occurred from 3 to 5 inches deep, especially for the seeds most affected by depth 

 of sowing. Deep seeding retarded the growth of small seeds and those having 

 poor germinating power more than it did the growth of larger seeds. The plants 

 usually grew faster when the seeds were sown from 1 to 2 inches deep. This 

 rapid growth was especially noticed with the roots, and is no doubt one of the 

 primary reasons for a larger yield from shallow sowings. In general, the height 

 above the soil decreased as the depth of sowing increased. The largest growth 

 above ground never occurred from seeds sown deeper than 3 inches. Small 

 seeds sown below 3 inches failed to reach the surface in twenty days. — F. G. A. 



Soya Bean, A Bacterial Blight of. By F. M. Coerper (Jour. Agr. Res. vol. xviii. 

 No. 4, Nov. 1919, pp. 179-194, 8 plates). — This paper described a new bacterial 

 blight, Bacterium glycineum (n.sp.), which attacks the leaves of the Soya Bean. 

 The disease forms small angular spots, which in the early stages are translucent, 

 but darken as the disease develops and finally drop out. The spots are found 

 also on the petioles and pods, and stems. B. glycineum is a rod form, motile, 

 with 1 or more flagella, and forms cream-coloured colonies on agar plates ; 

 non-liquefier ; best growth at 24 0 C. ; is sensitive to desiccation, and appears 

 to lose its pathogenic character when grown in artificial culture. It is able to 

 attack plants, and to enter the parenchyma without wounds in the epidermis 

 of the plant. — A. B. 



Spinach Blight and the relation of Insects to its Transmission. By J. A. 



McClintock and L. B. Smith (Jour. Agr. Res. xiv. pp. 1-60 ; July 1918 ; 

 plates). — Spinach Blight is characterized by mottling and malformation of 

 leaves and stunting of growth. No specific organism was found associated with 

 the disease, but sap from diseased plants was found to be infectious and to 

 reproduce the disease in healthy ones. The disease is probably not transmitted 

 by the seed, nor through the soil ; aphides, however, especially Macrosiphum 

 solanifolii are found to carry it and to remain infectious for a long time, especially 

 in the adult stage. The control of aphides is therefore regarded as the most 

 promising method of dealing with the disease. The symptoms described are 

 similar to those often observed in England. — -F. J. C. 



